From omicron to delta to alpha, COVID-19 has evolved many different strains.

The most infectious strains survive to spread to more people. Thus, the worst strains stay around for the longest.

Principle 1: Natural Selection is Determined by the Survival of the Fittest

You may have heard the term, “survival of the fittest”. Essentially, the organism that can best survive a given environment will continue to reproduce.

What is natural selection?

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Principle 2: Other Factors can also Determine Evolution

However, sometimes evolution does not progress to only favor the most fit. Evolution is a complicated process, and here are some other factors that can influence how evolution occurs:

Introductory video:

Advanced article to test challenge your knowledge: